An electrical signal is commonly carried by a pair of wires, wherein one wire carries a positive signal with respect to ground while the other carries a negative signal with respect to ground, to provide a balance around earth, or ground. The wires are twisted around each other, so any applied EMI (electromagnetic interference) is applied equally to the two wires and their voltage difference does not change. When pairs of wires are connected to a connector whose contacts are of flat configurations (and not twisted), and carry high frequency signals (usually over 1 MHz), there will be crosstalk between the connector contacts, wherein an emission (due to capacitive and inductive coupling) from one contact of a first pair of contacts, is picked up by one contact of a second pair but substantially not by the other contact of the second pair.
Crosstalk between adjacent lines or contacts of an electrical connector can be minimized by adding neutralizing capacitive couplings. For example, if initial contacts of two pairs lie adjacent but secondary contacts of the two pairs are far apart, crosstalk can be reduced by capacitively coupling each initial contact of a pair to the secondary contact of the other pair. Such coupling will result in transferring equal crosstalk voltages to the initial and secondary contacts of a pair, so the difference in voltage between the two contacts of the pair will not be changed. Prior attempts to capacitively or electromagnetically couple different contacts have involved modifications to the connector which were costly or unreliable. U.S. Pat. No. 5,186,647 owned by AT&T discloses an arrangement in which the middle of connector contacts cross one another so crosstalk is induced in opposite halves of the contact, in opposite phase, to effect cancellation. The re-entrant bends of such a connector are difficult to manufacture, especially because the location of the crossover points is critical. Also, this approach produces poor cancellation when the induction lengths are long, because the propagation delay prevents achievement of the required 180.degree. phase shift.
Another technique disclosed in European Patent Application 92112808.8 (0525703A1) owned by Siemen, employs a printed circuit board coupling with a double crossover of interfering lines to produce anti-phase coupling for crosstalk cancellation. This arrangement requires a separate printed circuit board with multiple crossing arrangements, which also adds to the expense. It is possible to use discrete capacitance or inductive couplings between contacts, but this is also costly and reduces reliability. An electrical connector with crosstalk compensation, which is reliable and relatively simple to manufacture while avoiding discrete components, would be of value.